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authorGuenter Roeck <linux@roeck-us.net>2018-09-11 11:18:12 -0700
committerThomas Gleixner <tglx@linutronix.de>2018-09-12 21:53:34 +0200
commitcf40361ede6cf9dc09349e4c049dc0d166ca2d8b (patch)
tree8832845b28d3efc4278209a47e72ce60708c8175 /arch/x86/platform/efi/efi_32.c
parent999696752db1099aba595aac4f8d881f8c7cf4e6 (diff)
x86/efi: Load fixmap GDT in efi_call_phys_epilog() before setting %cr3
Commit eeb89e2bb1ac ("x86/efi: Load fixmap GDT in efi_call_phys_epilog()") moved loading the fixmap in efi_call_phys_epilog() after load_cr3() since it was assumed to be more logical. Turns out this is incorrect: In efi_call_phys_prolog(), the gdt with its physical address is loaded first, and when the %cr3 is reloaded in _epilog from initial_page_table to swapper_pg_dir again the gdt is no longer mapped. This results in a triple fault if an interrupt occurs after load_cr3() and before load_fixmap_gdt(0). Calling load_fixmap_gdt(0) first restores the execution order prior to commit eeb89e2bb1ac and fixes the problem. Fixes: eeb89e2bb1ac ("x86/efi: Load fixmap GDT in efi_call_phys_epilog()") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: linux-efi@vger.kernel.org Cc: Andy Lutomirski <luto@amacapital.net> Cc: Joerg Roedel <jroedel@suse.de> Link: https://lkml.kernel.org/r/1536689892-21538-1-git-send-email-linux@roeck-us.net
Diffstat (limited to 'arch/x86/platform/efi/efi_32.c')
-rw-r--r--arch/x86/platform/efi/efi_32.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/x86/platform/efi/efi_32.c b/arch/x86/platform/efi/efi_32.c
index 05ca14222463..9959657127f4 100644
--- a/arch/x86/platform/efi/efi_32.c
+++ b/arch/x86/platform/efi/efi_32.c
@@ -85,10 +85,9 @@ pgd_t * __init efi_call_phys_prolog(void)
void __init efi_call_phys_epilog(pgd_t *save_pgd)
{
+ load_fixmap_gdt(0);
load_cr3(save_pgd);
__flush_tlb_all();
-
- load_fixmap_gdt(0);
}
void __init efi_runtime_update_mappings(void)

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